The Law defines what is good and what is evil, what is righteousness and what is sin. Sin uses the Law as an opportunity.
Step-by-step explanation:
If the people who lives in sin and is the slave of sin tries to follow the Old Testament law he cannot manage this, because the law doesn't provides any power, and sin uses this law to make us even more evil.
The law is good, but our nature is sinful. It finds out what is sinful and wants to practice, thus, sin uses the Law as an opportunity.
Victory over the sinful nature is possible only in Jesus Christ and only through faith in Him we receive forgiveness for all our sins.
The commandment of the Law is fulfilled only in those who have the Holy Spirit and live according to the Holy Spirit. May God help us all to live according to the Holy Spirit.